Enhanced electrochemical sensing of dopamine in the presence of AA and UA using curcumin functionalized gold nanoparticles modified electrode
In the present study, green synthesis of gold nanoparticle was carried out using curcumin as reducing and functionalizing agent. We have developed a chemically modified electrode using curcumin functionalized gold nanoparticles (CR-GNP) which act as a redox mediator for the electrochemical oxidation of dopamine in the presence of ascorbic acid, and uric acid. Overall CR-GNP is a stable electrode material, exhibited a synergetic effect towards enhanced electrochemical behavior, increased reaction kinetics, and selectivity in dopamine sensing. The surface characterization, surface composition, physio-chemical properties and electrochemical measurements were measured for CR-GNP modified electrode. This electrode exhibited an enhanced electrochemical behavior towards sensing of dopamine by minimizing the oxidation potential from +0.23V to +0.18V and the CR-GNP modified electrode showed higher oxidation peak current when compared with bare and curcumin modified electrode. Hydrodynamic measurement of dopamine was carried out using chronoamperometry technique and static measurement were carried out using cyclic voltammetry, linear sweep voltammetry techniques. Under optimal condition the modified electrode exhibited linearity in the calibration plot for dopamine concentration ranges from 0.4× 10-6 to 5.6 × 10-5 M. This work explores selectivity towards oxidation of dopamine in the presence ascorbic acid and uric acid with the detection limit of 4.2 × 10-8 M.